One for All, and All for Gilgamesh!

"★Celebrate MOBIUS FINAL FANTASY with the guy you hate to love, Gilgamesh★ Work together with your allies to unlock treasure chests."

- In-game description

One for All, and All for Gilgamesh! is a Ranked "battle tower" event available in January 2020. It features duels against Gilgamesh, with aid from the Moonlit Masquerade jobs. The contest was originally released as the Ranked Event for the game's 4th Anniversary in Japan.

This is Gilgamesh's penultimate appearance, so the rewards are extraordinarily valuable.

Event Details

 * Ranking Event duration: January 24 - February 1, 2020
 * Exhibition duration: February 1 - 8, 2020
 * Event type: progressive Tower Battle

The event is open for two weeks. The first week is the normal Ranked event. The second week players can continue to play it, and gain rewards for clearing areas, but the effort will not increase their ranking.

How to Participate

 * Select "One for All, and All for Gilgamesh!" from the Act 2 world map -- its own red spot.
 * This event is only accessible after a player clears the Runic Temple in Chapter 1

Story
Another day, another trip to the Tower of Trials. Given the recent Anniversary celebrations, it's no surprise that Gilgamesh shows up to celebrate in his own way. Wol is a bit bored of him, especially since his intro is still the same old thing, but Wol perks up a bit when Gilgamesh mentions he brought Wol's favourite: loot!

There's a bit of a catch, though. Every time Gilgamesh loses, he'll give up some Gilgamesh Coins, which Wol can use to get stuff. But he's going to need a LOT of them. Better bring some friends along! Of course, Wol has lots of friends now, so that shouldn't be too hard.

Even Echo admits that Gilgamesh's shtick is getting old...

Gameplay
Play in this area works up a single chain of levels, from the beginning Abyss level up to the top Ragnarok level. As you work your way up the tower, the battles at each level will get progressively harder.

Each battle has three skirmishes:
 * 1) The first one is against fiends meant to evoke the major events that occurred in the first year of the game.
 * 2) The second one has a featured ally from the Moonlit Masquerade. The ally will take all of the charge from your Ultimate Gauge, and reward you proportionally during the third skirmish.
 * 3) The third skirmish is always against Gilgamesh. He will work from his normal action list, but at the end of battle will gain, then throw s at you, causing minor damage.

Allies
Each battle will feature one of the five job classes from the Moonlit Masquerade. Depending on the amount of Ultimate Gauge you have to give, they will do a number of possible actions:
 * Cast their Ultimate Attack at Gilgamesh
 * Cast Prismatic Shift on you
 * Refill your entire Ultimate Gauge

Plus, each one will throw an extra effect that weakens Gilgamesh:

Event Map
"Your best frenemy, Gilgamesh, is back and ready to give you the pummeling we all know you deserve. This time, work together with your Warrior of Light allies to knock him all the way back to the Rift and maybe even receive rewards for doing so!"

- World Map description

The region is the standard Tower of Trials -- one path with a staircase, leading up to the top "Ragnarok" level. You cannot return to previous levels once they've been beaten.

After completing the Highest Level: Ragnarok, you enter the "Phantasmic Coil" areas. This is a set of 5 areas that repeat in an infinite loop, also with an increasing difficulty with each area finished. On these levels, there is no fifth Rental Card allowed, and if you lose, you cannot use s to continue. A Prize of x5 is handed out for each loop of 5 completed.

The Phantasmic Loop includes shortcuts. These allow the better players to skip ahead to the high-difficulty loops without needing to slog through the lower-level stuff. Completing a shortcut awards the s that would have been earned by going through those loops manually. Upon finishing the area, you're transported to The Phantasm as your starting point into the Phantasmic Loop. This is an irreversible jump -- once you complete one of the three initial areas, you're stuck on the Phantasmic Loop with that many "completions".
 * Beginner starts you at Loop 1 (11 kills). No shortcut, no award.
 * Intermediate starts you at Loop 6 (31 kills), x25,  x50
 * Advanced starts you at Loop 21 (106 kills), x100,  x395

There are 33 areas in total, including the Phantasmic Coil, the Starting Area, the shortcuts, and Gilgamesh's Secret Stash. There are 5 treasure chests, not including the rewards in the Stash. Since the treasure chest in the Phantasmic Coil regenerates on each pass, the region technically cannot be Completed.

Phantasmic Coil
The five levels after Ragnarok are set in an infinite loop, with a prize on the completion of the fifth area on each loop. Players cannot use s to continue the battle if they lose, and the fifth "rental" card is not available.

The skirmishes here have a pre-set collection of fiends, but after the 36th and 66th kill (?) they will change to other fiends. The third skirmish always remains as described.

Gilgamesh's Secret Stash!
s are earned by clearing each area. The total number of coins earned by ALL players in the game will be added up to unlock these areas, much like a Multiplayer "Defeat" campaign. No stamina or battles are needed to open these -- they are accessible as soon as the community accumulates enough total Coins.

By the end of the event, players had earned over 740,000 Coins, easily unlocking all of the stashes.

Ranking Rewards
With the announcement of the game's shutdown in 5 months, participation may be low, so anyone who completes all of the normal levels should make it within the top 10,000 players. The top 2,000 players will get s as a reward. These are used to open special high-end rewards in the Rift.

Notable Enemies

 * The Chocobo from Chocobocalypse
 * The Fire PuPu from PuPu Attacks!
 * The Tonberry from Karma Season
 * The Microchu from Collective Limit Break?
 * The Dark Moogle - Light from The Dark Moogles
 * Gilgamesh, of course!

Reference

 * Mobius Final Fantasy News Page Announcement
 * All for Gilgamesh setup guide on Reddit
 * BuffMeister's compilation of the videos from the event